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Home / Science / BECE Past Questions & Answers – 1990 (SCIENCE)

BECE Past Questions & Answers – 1990 (SCIENCE)

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August 1990

SCIENCE

SECTIONB ESSAY
1 hour [60 marks]

Answerthreequestionsonlyfrom this section.
Illustrate your answers wherever possible, with large, clear and fully labelled diagrams. Creditwill be given for clarity of expression and orderlypresentation ofmaterial.
Allquestions carry equal marks

1. (a) Defin ethefollowingterms and give one exampleof each:
(i) Compound
(ii) Mixture
(iii) Element
(iv) Solute

(b) What energychanges takeplacein thefollowingprocesses?
(i) (ii) (iii) A mango drops from atree.
A carpenterhits a nailwith a hammer. A torch is switched on.

(c)
(i) (ii)
Drawawelllabeled diagram of a flower
Ofwhat importanceis the flower to theplant?

(d)
Nam
e thesenseorgansand state one function of each.

2. (a) (i) What is soil erosion?Givetwo types of soil erosion.
(ii) Givethreeactivities ofman that cancause soil erosion.
(iii) Listthreeways bywhichsoil can be conserved.

(b) (i) What is a lever?
(ii) Classifythe followingunder first class, second class and third class levers.
Sugar tong
Bottle opener

Paper cutter
A pair ofscissors
Fishingrod
Clawhammer

(c) Ineach of the following activities, statewhetherthe changes that occurredare: (i) physical or chemical
(ii) reversible or irreversible
(α) Some boiled cassavaandplantain werepounded together into fufu.
(β) A pieceof iceblock is put in a cup. Afterawhile,itis found out that theblock had changed into aliquid
(γ) A clean pieceof nailwasput into a beaker of water. Afterfivedays itwas observed that thecolourofthe nailhad changed.

3. (a) Foreach of the following diseases, namethecausativeorganismand onemethod of prevention. (i) Cholera
(ii) Bilharzia
(iii) Malaria
(iv) Tuberculosis

(b) Show howyou would separateeach of the followingmixtures: (i) Common saltand sand
(ii) Muddywater

(c) Explain whythe planet and theirmoons move around the sun but theydo not clash. (d) Givetwo uses of thesun’s energyin everydaylife.

4. (a) (i) What is pollution?
(ii) Name two types of pollution. Foreach type,give onepollutant and its source.

(b) (i) (ii) Explain the term vegetative reproduction.
Give anytwo examples of plants that reproducevegetatively.

(c)
(i) (ii) (iii)
Listthe parts ofan atomand show the electricalcharges ofeach of theparts. Explain the term work.
Distinguish between heatand temperatureandgivetheirunits. CLICK TO VIEW ANSWERS TO PART 2

August 1990

SCIENCESectionB

SOLUTIONS

ESSAY

1. (a)

(i) Compound:
A substance formed bythe chemical combination ofelements in fixed proportions

Or: a substancecontainingtwo ormore elementsthat arechemicallycombined

(ii) Mixture
A physical combination of two ormoresubstances
Or:
A substance consistingof twoor moresubstancesthat havebeen combinedphysically

(iii) Element
A substancethat is madeup ofthe same kind of atoms
Or:
Anysubstancethat cannot be broken down into asimpleronebya chemical reaction

(iv) Solute
A substancethat is dissolved in anothersubstance

(b) Energy changes
(i) Amango drops fromatree.
Potential →Kinetic→Sound
(ii) A carpenterhits a nailwith a hammer.
Chemical→Potential →Kinetic→Sound +Heat
(iii) A torchis switchedon.
Chemical→Electrical →Light

(c) (i) A well-labeled diagramofaflower

1ci

(ii) Importanceof flower to plant
Sexual reproduction bysexcells
Seed development(ovuledevelops into seed)
Fruit production(ovarydevelops into fruit)
Attraction ofbirds and insects bypetals / nectar(for cross pollination)

(d) SENSEORGAN
Skin FUNCTION
Touch
Eye Sight
Nose Smell
Tongue Taste
Ear Hearing

2. (a) (i) Soilerosion
Thewashingawayof thetop soilbyagents of erosion
Or: The removal ofsoil material bynaturalprocesses,principallyrunning water, glaciers, waves, andwind

Types ofsoil erosion: Gully, Rill, Sheet and Splash [anytwo]

(ii) Activities ofmanthatcancausesoil erosion
 Removal of covercrops
 Bush burning
 Ploughing alongslopes
 Fellingof trees
 Sand-winning [anythree]

(iii) Ways by whichsoil canbe conserved
 Mulching
 Manuring

 PracticingCroprotation
 Plantingof cover crops
 Plantingmoretrees
 Practicingstripcropping

(b) (i) A lever
Simple machine consistingofa rigid barthatrotates about a fixed point, called apivot/
fulcrum

FIRST CLASS
SECONDCLASS
THIRD CLASS
A pair ofscissors
Clawhammer Bottle opener
Paper cutter Sugar tong fishingrod

(c) (i)Physical orchemical (ii) reversible orirreversible
(α) Some boiled cassavaandplantain werepounded together into fufu. (i) Physical (ii) irreversible

(β) A pieceof iceblock is put in a cup. Afterawhile,itis found out that theblock had changed into aliquid
(i) Physical (ii) reversible

(γ) A clean pieceof nailwasput into a beaker of water. Afterfivedays itwas observed that thecolourofthe nailhad changed
(i) chemical (ii) irreversible

3. (a)

DISEASE CAUSATIVE
ORGANISM
METHODOFPREVENTION

Cholera

bacteria
(Vibrio cholerae) Immunization /vaccination
Eatinghot meals
drinkingclean potablewater
washinghands with soapafter visitingthe toilet and beforemeals
coveringmeals to prevent flies from settlingon them
keepingour environment clean andfree from
filth
ensuringthat rubbish binsareproperlycovered

Bilharzia

flatworm
(blood fluke /schistosome) avoid touchingwaterbodies infected with the
vector (watersnails)
applychemicals to waterbodies infected with watersnails to kill thevector

Avoid pollutingwaterbodies

Malaria

Protozoon (plasmodium) Usingmosquito net
Usingmosquito repellent
Usinganti-malariadrugs
Clearingmosquito breeding grounds such as chokedgutters, stagnantpools of water,etc

Tuberculosis bacteria
(Mycobacterium tuberculosis) Immunization with BCGvaccine
Ensuring adequate ventilation
Avoid sharing cutlery, cups and glasses with infected persons [anyone for each]

(b) Howto separate themixtures: (i) Commonsalt andsand
I. Add waterto themixture and stir to dissolvethe salt
II. Pour the mixturethrougha filterpaper in a funnelto separate thesand (residue) from the saltsolution (filtrate)
III. Heat thesalt solution tillallthe waterevaporates,leavingthesalt crystals behind
IV. Drythe sand and thesalt obtained

(ii) Muddywater
 Fold a filterpaper into afunnel placed inabeaker.
 Pour themuddywaterthrough thefilterpaper in the funnel to separate thesuspended mud particles (residue)from thewater(filtrate)
 Thewater is collected inthe beaker, leavingthemud on the filterpaper.

(c) Why planets andtheir moonsmovearoundthesunwithout a clash
Each planetand each moon has a separate path (orbit) in whichit moves. Theyarekept in those separateorbits bythegravitational forces ofattraction between them and thelarger bodies
aroundwhich theymoveand hencedo not clash.

(d) Uses ofsun’s energy in everyday life
 Provision of light forseeing
 Dryingof clothes
 Preservation offoodbydrying
 Photosynthesisbygreenplants
 Electricitygeneration bysolar cells
 Synthesis of vitamin D bythe skin [anytwo]

4. (a) (i) Pollution
Contamination of Earth’senvironment with materials that interferewith human health,
the qualityof life, or thenatural functioningofecosystems

(ii)

TYPE OF POLLUTION POLLUTANT SOURCE

Air pollution

Smoke
carbonmonoxide

sulphurdioxide

Lead

Bush /tyreburning,
Motor-vehicle exhaust, Industrial processes
Sulphuric acid plants,
Power-generation facilities that useoilor coal containingsulphur
Motor-vehicle exhaust, batteryplants

Waterpollution

Sewage
 industrial wastes
 crudeoilspillage

Toxic chemicals
Homes, offices
Industries
Oil tankers, oil drilling rigs, oil refineries
Factories, Over-fertilized farmlands (through washing awaybyrain)

Land pollution Rubbish (non-
decomposable waste)

chemical fertilizers,

fungicides&pesticides Homes, offices,factories

Excessivefertilizer useby farmers
Indiscriminate application of fungicides and pesticides [anytwo types of pollution] [anyonepollutantand itssource for thetwo types]

(b) (i) Vegetativereproduction
Method bywhich plants reproducewithoutthe union of cells or nuclei of cells
Or:
Theprocess wherebyplants produceoffspring from growingparts / buds of theparent plant

(ii) Examples of plants that reproducevegetatively
Cassava, sugarcane,yam, cocoyam, banana, plantain, ginger, pineapple,etc

(c) (i) PART OFATOM ELECTRICALCHARGE
Proton +1
Neutron 0
Electron – 1

(ii) Work
Work is donewhen anapplied forcemoves an object in the direction oftheforce.
Or:
Thetransfer ofenergy, measuredas the product ofthe force applied to a bodyand the distancemoved bythat bodyin thedirection ofthe force
Or:
Work = f × d, where f = forceapplied
and d = distance moved in the directionoftheappliedforce

(iii)

HEAT TEMPERATURE
Theenergypossessed byabodythat
results in its hotness or coldness A measureof thehotnessor coldness
ofthe body

Unit = joule (J) Unit = kelvin (K) or
degeeCelsius (°C) or degreeFahrenheit(°F)

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